Rail-based transportation system, whether using a single rail, two rails, or an electromagnetic levitation system, are typically expensive to deploy. They usually necessitate extensive and permanent modifications to the ground surface in order to provide for the necessary infrastructure. Deployments of such systems may also be limited by the available space and/or the conditions of the ground surface. Moreover, conventional rail infrastructures are generally not easily adaptable for use under water or on less stable soil.
Screw-type propelling devices have been used for propulsion of inspection robots inside of a pipe. Such robots are typically completely contained inside the pipe and include at least one set of wheels having a helical trajectory against the inner surface of the pipe to propel the robot along the longitudinal direction of the pipe. Attempts have also been made to use such propelling devices as a vehicular drive, but the need for improvement still remains.